Amenorrhea, or absence of menstruation, occurs in as many as 25 percent of female high school athletes, compared with 2 to 5 percent in the general population, according to the study's presenter, Madhusmita Misra, MD, a pediatric endocrinologist at Harvard-affiliated Massachusetts General Hospital, Boston.

Amenorrhea in athletes is known to cause infertility and early onset of low bone density and may increase the risk of breaking bones. Evidence suggests that intense exercise associated with caloric restriction, and therefore a state of energy deficit, is most responsible for menstrual irregularities among athletes.

In females ages 12 to 18, Misra and her colleagues measured levels of various hormones, including ghrelin. Giving ghrelin to animals and humans has been shown to cause impaired secretion of hormones that regulate ovarian and menstrual function, and ghrelin levels are elevated in people with anorexia nervosa, another condition of severe energy deficit, she said. Until now, ghrelin levels have not been studied in teenage athletes in relation to ovarian hormones.

There are microbialites, strange coral-like growths, at the bottom of Pavilion Lake in British Columbia. They have been out of the reach of scientists but with the addition of new submersible technology they can now be studied.

The growths might, says Greg Slater, an environmental geochemist at McMaster University, hold the key to life beyond Earth.

These unique carbonate rock structures are known as microbialites because they are covered with microbes. Some of these microbialites grow at depths up to 180 feet below the water's surface, too deep to reach by non-decompression SCUBA diving.

The Y chromosome is an established evolutionary tool and has been used in many evolutionary studies. While easy to use, it has limitations which prevent it from full utilization about the most evolutionary informative DNA segments in the Human genome.

As part of her doctoral studies, Holly Leung in the Department of Genetics at University of Leicesteris has been investigating the potential of the X chromosome as another evolutionary informative segment in the human genome.

The University of Leicester has done many human population studies with the Y chromosome, including the relationship between the male surname and the Y chromosome, as well as a better understanding of the Viking settlement in the Northwest England.

In an effort to reconcile the science stating that power leads to action and lack of power leads to inhibition -- despite constant historical reminders of the powerless rising up and taking action -- new research in the June issue of Psychological Science, a journal of the Association for Psychological Science, suggests that the legitimacy of the power relationship is an important determinant of whether power leads to action.

The research, led in part by Kellogg School of Management Professor Adam Galinsky, sought to determine at what point the powerless rise up and take action. Galinsky collaborated with psychologist Joris Lammers of Tilburg University and Ernestine Gordijn and Sabine Otten of the University of Groninengen on the study. These findings are the first to clarify when, and lend insight into why, power leads to behavioral approach, or action.

The off-label use of a drug given with RU-486 to terminate a pregnancy may be responsible for a handful of rare, fatal infections seen in women taking the drugs since 2000, a study by University of Michigan scientists suggests. Preliminary U-M studies indicate that oral use of RU-486's companion drug misoprostol is safe, but vaginal use may undermine body's immune responses

The drug misoprostol is FDA-approved to be taken by mouth along with RU-486 to end a pregnancy. But many women have received the drug vaginally as part of the two-drug combination, a method of delivery not evaluated by the FDA.

In animal and cell culture studies, the U-M researchers found that misoprostol, when given directly in the reproductive tract, suppresses key immune responses and can allow a normally non-threatening bacterium, Clostridium sordellii, to gain the upper hand and cause deadly infection. When absorbed through the stomach, however, the drug did not compromise immune defenses or cause illness.

Since the Women's Health Initiative study found that long-term therapy with estrogen or estrogen plus progestin may increase the risk of heart attack and stroke, many women have found it difficult to decide whether to take hormone therapy at menopause.

Subsequently, several researchers have speculated that the timing of estrogen treatment may be important for estrogen's effects.

A group of authors therefore designed an animal study to determine if estrogen would be beneficial for females who are going through menopause (perimenopausal) but not for women who are postmenopausal for many years. Since it is not possible to measure "risk" in animal studies, the authors measured severity of stroke injury.